/*****************************************************************************
 * plum_kernel_print.c
 *
 * Copyright (C) 2020 Jeasonvor 1101627719@qq.com
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 ****************************************************************************/

/*****************************************************************************
 * Included Files
 ****************************************************************************/
#include "kernel/include/plum_kernel_api.h"
#include "float.h"
#include "stdint.h"
/*****************************************************************************
 * Trace Definitions
 ****************************************************************************/

/*****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

// internal flag definitions
#define FLAGS_ZEROPAD   (1U << 0U)
#define FLAGS_LEFT      (1U << 1U)
#define FLAGS_PLUS      (1U << 2U)
#define FLAGS_SPACE     (1U << 3U)
#define FLAGS_HASH      (1U << 4U)
#define FLAGS_UPPERCASE (1U << 5U)
#define FLAGS_CHAR      (1U << 6U)
#define FLAGS_SHORT     (1U << 7U)
#define FLAGS_LONG      (1U << 8U)
#define FLAGS_LONG_LONG (1U << 9U)
#define FLAGS_PRECISION (1U << 10U)
#define FLAGS_ADAPT_EXP (1U << 11U)

/*****************************************************************************
 * Private Types
 ****************************************************************************/

/**
 * @brief 定义输出函数类型
 */
typedef plum_void (*out_fct_type)(char character, plum_void* buffer, size_t idx,
                                  size_t maxlen);

/*****************************************************************************
 * Private Function Prototypes
 ****************************************************************************/

/*****************************************************************************
 * Private Data
 ****************************************************************************/

PLUM_PRIVATE
kernel_putchar_t plum_putchar = plum_null;
/*****************************************************************************
 * Public Data
 ****************************************************************************/

/*****************************************************************************
 * Private Functions
 ****************************************************************************/

// internal buffer output
PLUM_STATIC_INLINE
plum_void _out_buffer(char character, plum_void* buffer, size_t idx,
                      size_t maxlen)
{
    if (idx < maxlen) {
        ((char*)buffer)[idx] = character;
    }
}

// internal null output
PLUM_STATIC_INLINE
plum_void _out_null(char character, plum_void* buffer, size_t idx,
                    size_t maxlen)
{
    (plum_void) character;
    (plum_void) buffer;
    (plum_void) idx;
    (plum_void) maxlen;
}

// internal _putchar wrapper
PLUM_STATIC_INLINE
plum_void _out_char(char character, plum_void* buffer, size_t idx,
                    size_t maxlen)
{
    PLUM_UNUSED(buffer);
    PLUM_UNUSED(idx);
    PLUM_UNUSED(maxlen);
    if (character) {
        plum_putchar(character);
    }
}

/**
 * @brief 计算字符串长度
 *
 * @param[in]   str     -   字符串指针
 * @param[in]   maxsize -   支持最大字符串长度
 *
 * @return 返回实际字符串长度（包含结束符\0）
 */
PLUM_STATIC_INLINE
plum_u32 _strnlen_s(const char* str, size_t maxsize)
{
    const char* s;
    for (s = str; *s && maxsize--; ++s)
        ;
    return (plum_u32)(s - str);
}

/**
 * @brief 判断字符是否为数字
 *
 * @param[in]   ch  -   待判断字符
 *
 * @return 返回判断结果（true: 数字，false: 非数字）
 */
PLUM_STATIC_INLINE
plum_bit _is_digit(char ch)
{
    return (ch >= '0') && (ch <= '9');
}

/**
 * @brief 字符串转整型
 *
 * @param[in]   str     -   字符串指针
 *
 * @return 转换后的整形数据
 */
PLUM_PRIVATE plum_u32 _atoi(const char** str)
{
    plum_u32 i = 0U;
    while (_is_digit(**str)) {
        i = i * 10U + (plum_u32)(*((*str)++) - '0');
    }
    return i;
}

/**
 * @brief 内部保留的字符串输出函数
 *
 * @param[in]   out
 * @param[in]   buffer
 * @param[in]   idx
 * @param[in]   maxlen
 * @param[in]   buf
 * @param[in]   len
 * @param[in]   width
 * @param[in]   flags
 *
 * @return 返回输出的字符串长度
 */
PLUM_PRIVATE size_t _out_rev(out_fct_type out, char* buffer, size_t idx,
                             size_t maxlen, const char* buf, size_t len,
                             plum_u32 width, plum_u32 flags)
{
    const size_t start_idx = idx;

    // pad spaces up to given width
    if (!(flags & FLAGS_LEFT) && !(flags & FLAGS_ZEROPAD)) {
        for (size_t i = len; i < width; i++) {
            out(' ', buffer, idx++, maxlen);
        }
    }

    // reverse string
    while (len) {
        out(buf[--len], buffer, idx++, maxlen);
    }

    // append pad spaces up to given width
    if (flags & FLAGS_LEFT) {
        while (idx - start_idx < width) {
            out(' ', buffer, idx++, maxlen);
        }
    }

    return idx;
}

// internal itoa format
PLUM_PRIVATE size_t _ntoa_format(out_fct_type out, char* buffer, size_t idx,
                                 size_t maxlen, char* buf, size_t len,
                                 plum_bit negative, plum_u32 base,
                                 plum_u32 prec, plum_u32 width, plum_u32 flags)
{
    // pad leading zeros
    if (!(flags & FLAGS_LEFT)) {
        if (width && (flags & FLAGS_ZEROPAD) &&
            (negative || (flags & (FLAGS_PLUS | FLAGS_SPACE)))) {
            width--;
        }
        while ((len < prec) && (len < PRINTF_NTOA_BUFFER_SIZE)) {
            buf[len++] = '0';
        }
        while ((flags & FLAGS_ZEROPAD) && (len < width) &&
               (len < PRINTF_NTOA_BUFFER_SIZE)) {
            buf[len++] = '0';
        }
    }

    // handle hash
    if (flags & FLAGS_HASH) {
        if (!(flags & FLAGS_PRECISION) && len &&
            ((len == prec) || (len == width))) {
            len--;
            if (len && (base == 16U)) {
                len--;
            }
        }
        if ((base == 16U) && !(flags & FLAGS_UPPERCASE) &&
            (len < PRINTF_NTOA_BUFFER_SIZE)) {
            buf[len++] = 'x';
        }
        else if ((base == 16U) && (flags & FLAGS_UPPERCASE) &&
                 (len < PRINTF_NTOA_BUFFER_SIZE)) {
            buf[len++] = 'X';
        }
        else if ((base == 2U) && (len < PRINTF_NTOA_BUFFER_SIZE)) {
            buf[len++] = 'b';
        }
        if (len < PRINTF_NTOA_BUFFER_SIZE) {
            buf[len++] = '0';
        }
    }

    if (len < PRINTF_NTOA_BUFFER_SIZE) {
        if (negative) {
            buf[len++] = '-';
        }
        else if (flags & FLAGS_PLUS) {
            buf[len++] = '+';  // ignore the space if the '+' exists
        }
        else if (flags & FLAGS_SPACE) {
            buf[len++] = ' ';
        }
    }

    return _out_rev(out, buffer, idx, maxlen, buf, len, width, flags);
}

// internal itoa for 'long' type
PLUM_PRIVATE size_t _ntoa_long(out_fct_type out, char* buffer, size_t idx,
                               size_t maxlen, unsigned long value,
                               plum_bit negative, unsigned long base,
                               plum_u32 prec, plum_u32 width, plum_u32 flags)
{
    char   buf[PRINTF_NTOA_BUFFER_SIZE];
    size_t len = 0U;

    // no hash for 0 values
    if (!value) {
        flags &= ~FLAGS_HASH;
    }

    // write if precision != 0 and value is != 0
    if (!(flags & FLAGS_PRECISION) || value) {
        do {
            const char digit = (char)(value % base);
            buf[len++] =
                digit < 10 ? '0' + digit
                           : (flags & FLAGS_UPPERCASE ? 'A' : 'a') + digit - 10;
            value /= base;
        } while (value && (len < PRINTF_NTOA_BUFFER_SIZE));
    }

    return _ntoa_format(out, buffer, idx, maxlen, buf, len, negative,
                        (plum_u32)base, prec, width, flags);
}

#if defined(PRINTF_SUPPORT_FLOAT)

#if defined(PRINTF_SUPPORT_EXPONENTIAL)
// forward declaration so that _ftoa can switch to exp notation for values >
// PRINTF_MAX_FLOAT
PLUM_PRIVATE size_t _etoa(out_fct_type out, char* buffer, size_t idx,
                          size_t maxlen, double value, plum_u32 prec,
                          plum_u32 width, plum_u32 flags);
#endif

// internal ftoa for fixed decimal floating point
PLUM_PRIVATE size_t _ftoa(out_fct_type out, char* buffer, size_t idx,
                          size_t maxlen, double value, plum_u32 prec,
                          plum_u32 width, plum_u32 flags)
{
    char   buf[PRINTF_FTOA_BUFFER_SIZE];
    size_t len  = 0U;
    double diff = 0.0;

    // powers of 10
    PLUM_PRIVATE const double pow10[] = {
        1,      10,      100,      1000,      10000,
        100000, 1000000, 10000000, 100000000, 1000000000};

    // test for special values
    if (value != value)
        return _out_rev(out, buffer, idx, maxlen, "nan", 3, width, flags);
    if (value < -DBL_MAX)
        return _out_rev(out, buffer, idx, maxlen, "fni-", 4, width, flags);
    if (value > DBL_MAX)
        return _out_rev(out, buffer, idx, maxlen,
                        (flags & FLAGS_PLUS) ? "fni+" : "fni",
                        (flags & FLAGS_PLUS) ? 4U : 3U, width, flags);

    // test for very large values
    // standard printf behavior is to print EVERY whole number digit -- which
    // could be 100s of characters overflowing your buffers == bad
    if ((value > PRINTF_MAX_FLOAT) || (value < -PRINTF_MAX_FLOAT)) {
#if defined(PRINTF_SUPPORT_EXPONENTIAL)
        return _etoa(out, buffer, idx, maxlen, value, prec, width, flags);
#else
        return 0U;
#endif
    }

    // test for negative
    plum_bit negative = plum_false;
    if (value < 0) {
        negative = plum_true;
        value    = 0 - value;
    }

    // set default precision, if not set explicitly
    if (!(flags & FLAGS_PRECISION)) {
        prec = PRINTF_DEFAULT_FLOAT_PRECISION;
    }
    // limit precision to 9, cause a prec >= 10 can lead to overflow errors
    while ((len < PRINTF_FTOA_BUFFER_SIZE) && (prec > 9U)) {
        buf[len++] = '0';
        prec--;
    }

    int           whole = (int)value;
    double        tmp   = (value - whole) * pow10[prec];
    unsigned long frac  = (unsigned long)tmp;
    diff                = tmp - frac;

    if (diff > 0.5) {
        ++frac;
        // handle rollover, e.g. case 0.99 with prec 1 is 1.0
        if (frac >= pow10[prec]) {
            frac = 0;
            ++whole;
        }
    }
    else if (diff < 0.5) {
    }
    else if ((frac == 0U) || (frac & 1U)) {
        // if halfway, round up if odd OR if last digit is 0
        ++frac;
    }

    if (prec == 0U) {
        diff = value - (double)whole;
        if ((!(diff < 0.5) || (diff > 0.5)) && (whole & 1)) {
            // exactly 0.5 and ODD, then round up
            // 1.5 -> 2, but 2.5 -> 2
            ++whole;
        }
    }
    else {
        plum_u32 count = prec;
        // now do fractional part, as an unsigned number
        while (len < PRINTF_FTOA_BUFFER_SIZE) {
            --count;
            buf[len++] = (char)(48U + (frac % 10U));
            if (!(frac /= 10U)) {
                break;
            }
        }
        // add extra 0s
        while ((len < PRINTF_FTOA_BUFFER_SIZE) && (count-- > 0U)) {
            buf[len++] = '0';
        }
        if (len < PRINTF_FTOA_BUFFER_SIZE) {
            // add decimal
            buf[len++] = '.';
        }
    }

    // do whole part, number is reversed
    while (len < PRINTF_FTOA_BUFFER_SIZE) {
        buf[len++] = (char)(48 + (whole % 10));
        if (!(whole /= 10)) {
            break;
        }
    }

    // pad leading zeros
    if (!(flags & FLAGS_LEFT) && (flags & FLAGS_ZEROPAD)) {
        if (width && (negative || (flags & (FLAGS_PLUS | FLAGS_SPACE)))) {
            width--;
        }
        while ((len < width) && (len < PRINTF_FTOA_BUFFER_SIZE)) {
            buf[len++] = '0';
        }
    }

    if (len < PRINTF_FTOA_BUFFER_SIZE) {
        if (negative) {
            buf[len++] = '-';
        }
        else if (flags & FLAGS_PLUS) {
            buf[len++] = '+';  // ignore the space if the '+' exists
        }
        else if (flags & FLAGS_SPACE) {
            buf[len++] = ' ';
        }
    }

    return _out_rev(out, buffer, idx, maxlen, buf, len, width, flags);
}

#if defined(PRINTF_SUPPORT_EXPONENTIAL)
// internal ftoa variant for exponential floating-point type, contributed by
// Martijn Jasperse <m.jasperse@gmail.com>
PLUM_PRIVATE size_t _etoa(out_fct_type out, char* buffer, size_t idx,
                          size_t maxlen, double value, plum_u32 prec,
                          plum_u32 width, plum_u32 flags)
{
    // check for NaN and special values
    if ((value != value) || (value > DBL_MAX) || (value < -DBL_MAX)) {
        return _ftoa(out, buffer, idx, maxlen, value, prec, width, flags);
    }

    // determine the sign
    const plum_bit negative = value < 0;
    if (negative) {
        value = -value;
    }

    // default precision
    if (!(flags & FLAGS_PRECISION)) {
        prec = PRINTF_DEFAULT_FLOAT_PRECISION;
    }

    // determine the decimal exponent
    // based on the algorithm by David Gay
    // (https://www.ampl.com/netlib/fp/dtoa.c)
    union {
        plum_u64 U;
        double   F;
    } conv;

    conv.F   = value;
    int exp2 = (int)((conv.U >> 52U) & 0x07FFU) - 1023;  // effectively log2
    conv.U   = (conv.U & ((1ULL << 52U) - 1U)) |
             (1023ULL << 52U);  // drop the exponent so conv.F is now in [1,2)
    // now approximate log10 from the log2 integer part and an expansion of ln
    // around 1.5
    int expval = (int)(0.1760912590558 + exp2 * 0.301029995663981 +
                       (conv.F - 1.5) * 0.289529654602168);
    // now we want to compute 10^expval but we want to be sure it won't overflow
    exp2            = (int)(expval * 3.321928094887362 + 0.5);
    const double z  = expval * 2.302585092994046 - exp2 * 0.6931471805599453;
    const double z2 = z * z;
    conv.U          = (plum_u64)(exp2 + 1023) << 52U;
    // compute exp(z) using continued fractions, see
    // https://en.wikipedia.org/wiki/Exponential_function#Continued_fractions_for_ex
    conv.F *= 1 + 2 * z / (2 - z + (z2 / (6 + (z2 / (10 + z2 / 14)))));
    // correct for rounding errors
    if (value < conv.F) {
        expval--;
        conv.F /= 10;
    }

    // the exponent format is "%+03d" and largest value is "307", so set aside
    // 4-5 characters
    plum_u32 minwidth = ((expval < 100) && (expval > -100)) ? 4U : 5U;

    // in "%g" mode, "prec" is the number of *significant figures* not decimals
    if (flags & FLAGS_ADAPT_EXP) {
        // do we want to fall-back to "%f" mode?
        if ((value >= 1e-4) && (value < 1e6)) {
            if ((int)prec > expval) {
                prec = (unsigned)((int)prec - expval - 1);
            }
            else {
                prec = 0;
            }
            flags |= FLAGS_PRECISION;  // make sure _ftoa respects precision
            // no characters in exponent
            minwidth = 0U;
            expval   = 0;
        }
        else {
            // we use one sigfig for the whole part
            if ((prec > 0) && (flags & FLAGS_PRECISION)) {
                --prec;
            }
        }
    }

    // will everything fit?
    plum_u32 fwidth = width;
    if (width > minwidth) {
        // we didn't fall-back so subtract the characters required for the
        // exponent
        fwidth -= minwidth;
    }
    else {
        // not enough characters, so go back to default sizing
        fwidth = 0U;
    }
    if ((flags & FLAGS_LEFT) && minwidth) {
        // if we're padding on the right, DON'T pad the floating part
        fwidth = 0U;
    }

    // rescale the float value
    if (expval) {
        value /= conv.F;
    }

    // output the floating part
    const size_t start_idx = idx;
    idx = _ftoa(out, buffer, idx, maxlen, negative ? -value : value, prec,
                fwidth, flags & ~FLAGS_ADAPT_EXP);

    // output the exponent part
    if (minwidth) {
        // output the exponential symbol
        out((flags & FLAGS_UPPERCASE) ? 'E' : 'e', buffer, idx++, maxlen);
        // output the exponent value
        idx = _ntoa_long(out, buffer, idx, maxlen,
                         (expval < 0) ? -expval : expval, expval < 0, 10, 0,
                         minwidth - 1, FLAGS_ZEROPAD | FLAGS_PLUS);
        // might need to right-pad spaces
        if (flags & FLAGS_LEFT) {
            while (idx - start_idx < width)
                out(' ', buffer, idx++, maxlen);
        }
    }
    return idx;
}
#endif  // PRINTF_SUPPORT_EXPONENTIAL
#endif  // PRINTF_SUPPORT_FLOAT

// internal itoa for 'long long' type
#if defined(PRINTF_SUPPORT_LONG_LONG)
PLUM_PRIVATE size_t _ntoa_long_long(out_fct_type out, char* buffer, size_t idx,
                                    size_t maxlen, unsigned long long value,
                                    plum_bit negative, unsigned long long base,
                                    plum_u32 prec, plum_u32 width,
                                    plum_u32 flags)
{
    char   buf[PRINTF_NTOA_BUFFER_SIZE];
    size_t len = 0U;

    // no hash for 0 values
    if (!value) {
        flags &= ~FLAGS_HASH;
    }

    // write if precision != 0 and value is != 0
    if (!(flags & FLAGS_PRECISION) || value) {
        do {
            const char digit = (char)(value % base);
            buf[len++] =
                digit < 10 ? '0' + digit
                           : (flags & FLAGS_UPPERCASE ? 'A' : 'a') + digit - 10;
            value /= base;
        } while (value && (len < PRINTF_NTOA_BUFFER_SIZE));
    }

    return _ntoa_format(out, buffer, idx, maxlen, buf, len, negative,
                        (plum_u32)base, prec, width, flags);
}
#endif  // PRINTF_SUPPORT_LONG_LONG

// internal vsnprintf
PLUM_PRIVATE int _vsnprintf(out_fct_type out, char* buffer, const size_t maxlen,
                            const char* format, va_list va)
{
    plum_u32 flags, width, precision, n;
    size_t   idx = 0U;

    if (!buffer) {
        // use null output function
        out = _out_null;
    }

    while (*format) {
        // format specifier?  %[flags][width][.precision][length]
        if (*format != '%') {
            // no
            out(*format, buffer, idx++, maxlen);
            format++;
            continue;
        }
        else {
            // yes, evaluate it
            format++;
        }

        // evaluate flags
        flags = 0U;
        do {
            switch (*format) {
                case '0':
                    flags |= FLAGS_ZEROPAD;
                    format++;
                    n = 1U;
                    break;
                case '-':
                    flags |= FLAGS_LEFT;
                    format++;
                    n = 1U;
                    break;
                case '+':
                    flags |= FLAGS_PLUS;
                    format++;
                    n = 1U;
                    break;
                case ' ':
                    flags |= FLAGS_SPACE;
                    format++;
                    n = 1U;
                    break;
                case '#':
                    flags |= FLAGS_HASH;
                    format++;
                    n = 1U;
                    break;
                default:
                    n = 0U;
                    break;
            }
        } while (n);

        // evaluate width field
        width = 0U;
        if (_is_digit(*format)) {
            width = _atoi(&format);
        }
        else if (*format == '*') {
            const int w = va_arg(va, int);
            if (w < 0) {
                flags |= FLAGS_LEFT;  // reverse padding
                width = (plum_u32)-w;
            }
            else {
                width = (plum_u32)w;
            }
            format++;
        }

        // evaluate precision field
        precision = 0U;
        if (*format == '.') {
            flags |= FLAGS_PRECISION;
            format++;
            if (_is_digit(*format)) {
                precision = _atoi(&format);
            }
            else if (*format == '*') {
                const int prec = (int)va_arg(va, int);
                precision      = prec > 0 ? (plum_u32)prec : 0U;
                format++;
            }
        }

        // evaluate length field
        switch (*format) {
            case 'l':
                flags |= FLAGS_LONG;
                format++;
                if (*format == 'l') {
                    flags |= FLAGS_LONG_LONG;
                    format++;
                }
                break;
            case 'h':
                flags |= FLAGS_SHORT;
                format++;
                if (*format == 'h') {
                    flags |= FLAGS_CHAR;
                    format++;
                }
                break;
#if defined(PRINTF_SUPPORT_PTRDIFF_T)
            case 't':
                flags |= (sizeof(ptrdiff_t) == sizeof(long) ? FLAGS_LONG
                                                            : FLAGS_LONG_LONG);
                format++;
                break;
#endif
            case 'j':
                flags |= (sizeof(intmax_t) == sizeof(long) ? FLAGS_LONG
                                                           : FLAGS_LONG_LONG);
                format++;
                break;
            case 'z':
                flags |= (sizeof(size_t) == sizeof(long) ? FLAGS_LONG
                                                         : FLAGS_LONG_LONG);
                format++;
                break;
            default:
                break;
        }

        // evaluate specifier
        switch (*format) {
            case 'd':
            case 'i':
            case 'u':
            case 'x':
            case 'X':
            case 'o':
            case 'b':
            {
                // set the base
                plum_u32 base;
                if (*format == 'x' || *format == 'X') {
                    base = 16U;
                }
                else if (*format == 'o') {
                    base = 8U;
                }
                else if (*format == 'b') {
                    base = 2U;
                }
                else {
                    base = 10U;
                    flags &= ~FLAGS_HASH;  // no hash for dec format
                }
                // uppercase
                if (*format == 'X') {
                    flags |= FLAGS_UPPERCASE;
                }

                // no plus or space flag for u, x, X, o, b
                if ((*format != 'i') && (*format != 'd')) {
                    flags &= ~(FLAGS_PLUS | FLAGS_SPACE);
                }

                // ignore '0' flag when precision is given
                if (flags & FLAGS_PRECISION) {
                    flags &= ~FLAGS_ZEROPAD;
                }

                // convert the integer
                if ((*format == 'i') || (*format == 'd')) {
                    // signed
                    if (flags & FLAGS_LONG_LONG) {
#if defined(PRINTF_SUPPORT_LONG_LONG)
                        const long long value = va_arg(va, long long);
                        idx                   = _ntoa_long_long(
                            out, buffer, idx, maxlen,
                            (unsigned long long)(value > 0 ? value : 0 - value),
                            value < 0, base, precision, width, flags);
#endif
                    }
                    else if (flags & FLAGS_LONG) {
                        const long value = va_arg(va, long);
                        idx              = _ntoa_long(
                            out, buffer, idx, maxlen,
                            (unsigned long)(value > 0 ? value : 0 - value),
                            value < 0, base, precision, width, flags);
                    }
                    else {
                        const int value = (flags & FLAGS_CHAR)
                                              ? (char)va_arg(va, int)
                                              : (flags & FLAGS_SHORT)
                                                    ? (short int)va_arg(va, int)
                                                    : va_arg(va, int);
                        idx = _ntoa_long(
                            out, buffer, idx, maxlen,
                            (plum_u32)(value > 0 ? value : 0 - value),
                            value < 0, base, precision, width, flags);
                    }
                }
                else {
                    // unsigned
                    if (flags & FLAGS_LONG_LONG) {
#if defined(PRINTF_SUPPORT_LONG_LONG)
                        idx = _ntoa_long_long(out, buffer, idx, maxlen,
                                              va_arg(va, unsigned long long),
                                              plum_false, base, precision,
                                              width, flags);
#endif
                    }
                    else if (flags & FLAGS_LONG) {
                        idx = _ntoa_long(out, buffer, idx, maxlen,
                                         va_arg(va, unsigned long), plum_false,
                                         base, precision, width, flags);
                    }
                    else {
                        const plum_u32 value =
                            (flags & FLAGS_CHAR)
                                ? (unsigned char)va_arg(va, plum_u32)
                                : (flags & FLAGS_SHORT)
                                      ? (unsigned short int)va_arg(va, plum_u32)
                                      : va_arg(va, plum_u32);
                        idx = _ntoa_long(out, buffer, idx, maxlen, value,
                                         plum_false, base, precision, width,
                                         flags);
                    }
                }
                format++;
                break;
            }
#if defined(PRINTF_SUPPORT_FLOAT)
            case 'f':
            case 'F':
                if (*format == 'F')
                    flags |= FLAGS_UPPERCASE;
                idx = _ftoa(out, buffer, idx, maxlen, va_arg(va, double),
                            precision, width, flags);
                format++;
                break;
#if defined(PRINTF_SUPPORT_EXPONENTIAL)
            case 'e':
            case 'E':
            case 'g':
            case 'G':
                if ((*format == 'g') || (*format == 'G'))
                    flags |= FLAGS_ADAPT_EXP;
                if ((*format == 'E') || (*format == 'G'))
                    flags |= FLAGS_UPPERCASE;
                idx = _etoa(out, buffer, idx, maxlen, va_arg(va, double),
                            precision, width, flags);
                format++;
                break;
#endif  // PRINTF_SUPPORT_EXPONENTIAL
#endif  // PRINTF_SUPPORT_FLOAT
            case 'c':
            {
                plum_u32 l = 1U;
                // pre padding
                if (!(flags & FLAGS_LEFT)) {
                    while (l++ < width) {
                        out(' ', buffer, idx++, maxlen);
                    }
                }
                // char output
                out((char)va_arg(va, int), buffer, idx++, maxlen);
                // post padding
                if (flags & FLAGS_LEFT) {
                    while (l++ < width) {
                        out(' ', buffer, idx++, maxlen);
                    }
                }
                format++;
                break;
            }

            case 's':
            {
                const char* p = va_arg(va, char*);
                plum_u32 l = _strnlen_s(p, precision ? precision : (size_t)-1);
                // pre padding
                if (flags & FLAGS_PRECISION) {
                    l = (l < precision ? l : precision);
                }
                if (!(flags & FLAGS_LEFT)) {
                    while (l++ < width) {
                        out(' ', buffer, idx++, maxlen);
                    }
                }
                // string output
                while ((*p != 0) &&
                       (!(flags & FLAGS_PRECISION) || precision--)) {
                    out(*(p++), buffer, idx++, maxlen);
                }
                // post padding
                if (flags & FLAGS_LEFT) {
                    while (l++ < width) {
                        out(' ', buffer, idx++, maxlen);
                    }
                }
                format++;
                break;
            }

            case 'p':
            {
                width = sizeof(plum_void*) * 2U;
                flags |= FLAGS_ZEROPAD | FLAGS_UPPERCASE;
#if defined(PRINTF_SUPPORT_LONG_LONG)
                const plum_bit is_ll = sizeof(uintptr_t) == sizeof(long long);
                if (is_ll) {
                    idx = _ntoa_long_long(out, buffer, idx, maxlen,
                                          (uintptr_t)va_arg(va, plum_void*),
                                          plum_false, 16U, precision, width,
                                          flags);
                }
                else {
#endif
                    idx = _ntoa_long(
                        out, buffer, idx, maxlen,
                        (unsigned long)((uintptr_t)va_arg(va, plum_void*)),
                        plum_false, 16U, precision, width, flags);
#if defined(PRINTF_SUPPORT_LONG_LONG)
                }
#endif
                format++;
                break;
            }

            case '%':
                out('%', buffer, idx++, maxlen);
                format++;
                break;

            default:
                out(*format, buffer, idx++, maxlen);
                format++;
                break;
        }
    }

    // termination
    out((char)0, buffer, idx < maxlen ? idx : maxlen - 1U, maxlen);

    // return written chars without terminating \0
    return (int)idx;
}

/*****************************************************************************
 * Public Functions
 ****************************************************************************/

PLUM_PUBLIC
plum_s32 plum_kernel_register_putchar(kernel_putchar_t func)
{
    if (plum_putchar != plum_null) {
        plum_putchar = func;
        return (PLUM_ECODE_OK);
    }
    else {
        return (PLUM_ECODE_INVALID);
    }
}

plum_s32 plum_printf(PLUM_CONST plum_s8* format, ...)
{
    va_list va;
    va_start(va, format);
    char      buffer[1];
    const int ret = _vsnprintf(_out_char, buffer, (size_t)-1, format, va);
    va_end(va);
    return ret;
}

plum_s32 plum_sprintf(plum_s8* buffer, PLUM_CONST plum_s8* format, ...)
{
    va_list va;
    va_start(va, format);
    const int ret = _vsnprintf(_out_buffer, buffer, (size_t)-1, format, va);
    va_end(va);
    return ret;
}

plum_s32 plum_snprintf(plum_s8* buffer, size_t count,
                       PLUM_CONST plum_s8* format, ...)
{
    va_list va;
    va_start(va, format);
    const int ret = _vsnprintf(_out_buffer, buffer, count, format, va);
    va_end(va);
    return ret;
}

plum_s32 plum_vsnprintf(plum_s8* buffer, size_t count,
                        PLUM_CONST plum_s8* format, va_list va)
{
}

plum_s32 plum_vprintf(PLUM_CONST plum_s8* format, va_list va)
{
}

/****************************************************************************/
/*                                                                          */
/*  End of file.                                                            */
/*                                                                          */
/****************************************************************************/
